June 2005

Making the Cut

Each year dozens of new cultivars are released from plant breeders, propagators and suppliers. These cultivars are evaluated in the National Annual and Perennial Cut Flower Trial Programs, administered by NC State University and the Association of Specialty Cut Flower Growers (ASCFG). The new cultivars are tested at more than 40 locations in the United States and Canada, providing valuable information on yield, stem length and market appeal. However, a new cut flower must also have a long postharvest life.

This study screened 50 new cut flower species/cultivars over three years to determine which ones have a long postharvest life. We selected those cultivars that performed well in the NC State cut flower trials (See GPN April 2005 for those results). Most of the cultivars were field-grown, but several were also greenhouse grown.

Methods

Field-grown flowers were harvested into tap water at the optimum stage of flower development. The stems were subsequently, sorted and placed in the following treatments:

• hydrator only,
• holding preservative only,
• hydrator followed by holding preservative and
• distilled water only (control).

The hydrator we used was Chrysal Professional 1 Processing Solution, and the holding preservative we used was Chrysal Professional 2 Processing Solution. Other companies have similar products that should give similar results. We used the products from only one company because we did not have enough plant material to test all of the appropriate products.

Dianthus
These cultivars had a long vase life, more than 15 days, when holding preservatives were used. Hydrating solutions did not have an effect on any of the cultivars.

‘Amazon Neon’. This brilliantly colored flower had a vase life of 15 days when a holding solution was used.

‘Bouquet Purple’. Another of the new heat-tolerant dianthus that had a vase life of 18-19 days when placed in a holding solution.

‘Sweet Coral’ and ‘Sweet Red’. This Sweet William flowers rapidly from seed in the first year. Cut stems should be treated only with the holding preservative, which produced a 15- to 20-day vase life. However, using only water produced a 12- to 15-day vase life. Combining the hydrator with the holding preservative caused leaf browning.

Eustoma
These popular flowers performed best when treated with a holding preservative. Hydrating preservatives did not have any effect on the cultivars tested.
‘Twinkle Blue Blush’ and ‘Twinkle Pink’. Placing the stems in water only produced a 17- to 18-day vase life. The holding preservative increased the vase life by 2-3 days.

‘Alice Pink’. A vase life of 17-21 days was obtained with a holding solution.
‘Malibu Purple’. A vase life of 12 days was obtained with a holding solution.

Sunflower
The best handling treatment for most cultivars was to cut them in plain water, and either transfer to a commercial floral holding preservative or leave them in plain water.

‘ProCut Orange’. This pollen-free sunflower had 3- to 4-inch-wide flowers that lasted up to 12 days. Using both hydrator and holding preservatives decreased vase life to five days.

‘ProCut Bicolor’. This sunflower has a mahogany ring around the dark center disc and lasted 9-10 days regardless of treatment.

‘Full Sun’. This traditional appearing sunflower can be difficult to handle due to the very large head. Vase life averaged 7-10 days.

‘The Joker’. Vase life averaged 7-10 days.

‘Lemon Éclair’. Vase life averaged eight days regardless of treatment.

‘Stella Gold’. A holding solution increased the vase life by only one day compared to water only, which was seven days.

‘Sunny’. The holding preservative caused some petal tip browning. Vase life averaged 14-17 days.

‘Terracotta’. The primary flower expanded, and the color deepened as it aged. Side floral buds opened, which may increase the consumer vase life, but our testing focused on the main flower. Vase life averaged 12-15 days.
Rudbeckia

The three cultivars had a long postharvest life — a minimum of 13 days. ‘Prairie Sun’ lasted the longest, more than 21 days. While the optimum treatments varied with

the cultivar, the longest vase life was generally obtained with the use of a hydration solution followed by a holding preservative solution.

‘Autumn Colors’. Placed stems into a hydration solution followed by a holding solution. Powdery mildew developed on the foliage and outer flower petals of some stems as they aged. Botrytis was also observed on some stems.

‘Goldie Locks’. Placed stems into a hydration solution and then transferred to water. Some Botrytis was observed in the flower center.

‘Prairie Sun’. All treatments produced long-lasting flowers. Placed in a hydration solution and then transferred to a holding solution. Browning was not observed.

Zinnia
Zinnias often have problems with postharvest life and are very susceptible to dirty postharvest water. However, we found the best result for the cultivars we tested was to either cut into a hydrator or into plain water. Most cultivars were damaged when both a hydrator and holding preservative were used.

‘Benary’s Giant Lime’. This flower should be placed directly into clean, high-quality water to obtain a 231?2-day vase life. Hydrating and holding solutions decreased vase life; when both were used together the vase life was only 1.3 days.

‘Sun Cherry’ and ‘Sun Gold’. These flowers should be placed directly into clean, high-quality water to obtain an 11- to 12-day vase life. Holding solution decreased vase life.

‘Oklahoma Carmine’. All treatments resulted in a long vase life with no detrimental effects for this bright-rose-colored zinnia. The stems in water-only lasted 19 days, while the vase life was 20 days for stems pretreated with the hydrator and placed in water.

‘Oklahoma Yellow’. A vase life of 24 days resulted when using only the hydrator; however, stems in water lasted 22 days.

Others
Achillea ‘Cassis’. This flower should be placed directly into clean, high-quality water to obtain a 12-day vase life. Hydrating and holding solutions decreased vase life.

Adenophora ‘Amethyst’. This species had long stems with pendulous, blue, bell-shaped flowers and a vase life of 11 days in water. A holding solution increased the vase life by three days.

Agapanthus ‘MidKnight Blue’. This bulbous perennial had a 10- to 11-day vase life in high-quality water. Commercial preservatives had no effect.
Ammi ‘Casablanca’. A 15-day vase life was obtained with water. Commercial preservatives were not effective.

Campanula rapunculus ‘Heav-enly Blue’. The stems of this new annual were covered with many delicate, light-blue, bell-shaped flowers. An 11- to 15-day vase life was obtained in water. Commercial preservatives were not effective.
Campanula takesimana ‘Kent Belle’. A hydrator only or hydrator and holding preservative extended the vase life of this traditional, deep-blue, perennial, bell flower by 3-4 days over the control, which lasted 10-12 days. Florets did not drop as the stems matured.

Caryopteris ‘First Choice’. This small shrub produced whorls of blue flowers that lasted 14-15 days. Floral preservatives were not effective.
Celosia ‘Toreador Red’. An amazingly long-lasting flower. A vase life of 33 days was obtained by using a holding solution. Hydrating solution had no effect.
Dahlia ‘Karma Naomi’ and ‘Karma Thalia’. Vase life averaged 5-6 days regardless of treatment.

Foxglove ‘Camelot Lavender’ and ‘Camelot Rose’. This new series of foxglove flowers in the first year from seed. Placing the stems in holding preservative added only one day to those held in water, which had a vase life of 8-9 days.
Eupatorium cannabinum. Flow-ers last 20-24 days regardless of treatment.
Gladiolus callianthus (Acid-anthera). This species, which is related to the common gladiolus, had a 10-day vase life when a holding solution was used. Hydrating solution had no effect.

Helenium ‘Helena Gold’ and ‘Helena Red Shades’. This daisy-like flower lasted 16 days in water only. It was able to tolerate the use of either a holding or a hydrating solution but not the use of both, which reduced vase life.

Heliopsis helianthoides ‘Sum-mer Sun’. This bright-yellow perennial continued to flower throughout the summer. Using only the hydrator extended the vase life eight days beyond that of stems held in water, which lasted 11 days. The vase life was Á reduced to seven days when treated with both hydrating and holding solutions.

Helianthus salicifolius ‘First Light’. Stems should be placed into either water or hydrator and then into a holding solution. This treatment produced a vase life of 12-18 days. This cultivar has multiple 2- to 21?2-inch flowers that open from the base of the inflorescence. Stems were harvested when one or tw0o flowers were open. They made impressive bright-yellow sprays when fully open. No browning was observed in any treatment.

Leucanthemum ‘Polaris’. This classic daisy lasted 121?2 days with a holding solution. Hydrating solution had no effect.

Lobelia ‘Fan Blue’. The stems of deep-blue florets with lustrous green foliage lasted eight days in water only. A holding preservative only added 1-2 days.
Matricaria ‘Magic Lime Green’. Vase life in water only was 20 days. The holding preservative increased the vase life four days.

Persicaria ‘Silver Dragon’. Grown for its burgundy, green and silver foliage, this species had a vase life of more than three weeks. As a result, stems tended to root.
Physostegia ‘Summer Spires’. A vase life of 15 days was obtained with a holding solution. Hydrating solution had no effect.

Scabiosa ‘Qis Deep Red’. A holding solution had a slight effect and increased vase life only by one day compared to water only, which was seven days.

Trachelium ‘Summer Purple’ and ‘Summer White’. A vase life of 12-13 days was obtained using a holding solution. Hydrating solution had no effect.

John Dole, William Fonteno and Sylvia Blankenship are professors; Frankie Fanelli is a former graduate student and Beth Harden is a research technician all from North Carolina State University, Raleigh, N.C.

Author’s Note: We would like to thank the American Floral Endowment and the Association of Specialty Cut Flower Growers for funding this work. Thanks to Ingram McCall and Diane Mays for growing the flowers and for assisting with postharvest testing. Thanks also to the many seed and plant suppliers who provided the plant materials as part of the ASCFG Trial Programs.